class Animal:
    def __init__(self,name,age):
        self.name=name
        self.age=age

    def eat(self):
        print(f'{self.name}正在吃东西')

    def drink(self):
        print(f'{self.name}正在喝水')

class Dog(Animal):
    def guard(self):
        print(f'{self.name}正在看门')


class XtDog(Dog):
    def fly(self):
        print(f'{self.name}正在飞')

xtq=XtDog('哮天犬','18')
xtq.guard()
xtq.fly()